Ce0.80M0.12Sn0.08O2-δ (M = Hf, Zr, Pr, and La) ternary oxide solid solutions with superior properties for CO oxidation

To develop efficient materials for CO oxidation, a series of co-doped CeO2 ternary oxide solid solutions (Ce0.80M0.12Sn0.08O2-delta, M = Hf, Zr, Pr, and La) were prepared by a simple coprecipitation method. The fundamental characteristics of the co-doped CeO2 samples were studied by X-ray diffraction, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy, transmission electron microscopy, Brunauer-Emmett-Teller surface area, H-2-temperature programmed reduction, X-ray photoelectron spectroscopy, and O-2-temperature programmed desorption. The oxidation of CO was chosen as a model reaction to evaluate the catalytic performance of these samples. The characterization results revealed that ternary oxide solid solutions had significantly enhanced surface area, improved reducibility, increased oxygen mobility and higher quantity of surface adsorbed oxygen species and oxygen vacancies, compared to undoped CeO2. The CO oxidation performance of CeO2 was greatly improved upon co-doping due to the modification in structural, textural, and redox properties. Especially, the Ce0.80Pr0.12Sn0.08O2-delta combination catalyst exhibited the highest oxidation activity among the investigated samples, which is attributed to its high specific surface area, better reducibility, superior surface active oxygen species, and oxygen vacancies among the various samples investigated.